Ice-making machine



lab. 22, 1952 Filed May 5, 1949 G. F. ERICKSON ET AL 2,583,294

ICE-MAKING MACHINE 5 Sheets-Sheet l 1 I l I INVENTORS.

Jan. 22, 1952 G. F. ERICKSON ETAL ICE-MAKING MACHINE 5 Sheets-Sheet 2 Filed May 5, 1949 l I v mmvroxs.

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1952 G. F. ERICKSON ET AL 2,583, 4

I ICE-MAKING MACHINE Filed May 5, 1949 '5 Sheets-Sheet 4 INVENTORJ. Gasmr f. Inc/(5am .PdRNO/V .5.

Jan. 22, 1952 e. F. ERICKSON ET AL 255515.2 4.-

ICE-MAKING MACHINE Filed May 5, 1949 5 Sheec-Sheet O -1=1| a a I 1 1i. 1n 77 Patented Jan. 22, 1952 1: UNITED STATES ATENT OFFICE ICE-MAKING MACHINE- Gustav F. Erickson andilormon. B.v McShan,,Indianapolis, Indi, assignors, by memo assignments, to Icecrafter Trust, a trust comprised of John R. Bayston, Van" Nuys; B'crnidineB-l Oliver,- North Hollywood; G'alifi, and Wardi Vmderpool, Rockford; 111., as trustees; Application May 3', 1949., SerialiNo. 91,088

19 Claims;

This invention relates to a. machine for manufacturing and delivering ice cubes automatically wherein a number of individual ice cubes are simultaneously frozen and thereupon automatically released from their freezing cells for discharge to a delivery chute, as generally disclosed l in the application ofJohnR'. Bayston,. SerialiNo.

80,265,. filed March 8', 1949, for Ice Making. lviachine, now Patent No; 2,563,093.

One object of." the invention is to provide a structure and mechanism applicable to a maing an apertured plate in the liquid and beneath the group of cells within-the freezing unit adapted to be vibrated toward and. away from the cells for pulsating; the liquid centrally thereof. Such pulsations provide just. sufiicient agitation of the liquid in: each cell to permit freezing. about the surface thereof while maintaining a washing; action for. removing impurties. as the freezing proresses.

A feature of the invention resides in the structural mounting of the refrigerant channel or coils of the evaporator. relative to the freezing cells for accomplishing the twofold. purpose of providing. maximum efliciency in the heat transfer therebetween and permit of economic and convenient manufacture of the freezing unit.

A further featureof the invention resides in themechanism for lowering and raising the closure or platen from and-toward the open bottom ofthe cells, with. means for providing a pause during the lowering movement to permit-complete freeing thereof from the formed icein the cellsbefore being permitted to dropv to its extreme open and ice discharging, position.

An additional feature. involves the separation of theice cubes from the excess liquid and impurities. trapped or remaining therein. The ice cubes, being frozen free of the impurities carried by the liquid; are discharged over an apertured chute into a container free of liquid; the unfrozen liquid being first dumped or spilled overthc chute to pass therethrough into a drain sump.

Other'features of the invention reside in the control circuit and inechanism operated thereby to effect complete automatic operation of the machine to insure continuous production through alternate freezing; releasing; and discharging of frozen cubes;

The full nature of theinvention'will be understood" from the" accompanying drawings" and the following description and claims:

Fig: l is a side elevation of the machine with corer'pl'ates removed showing the closure platen in freezing position by full lines; and discharge position by dotted lines:

Fig; 2 is the same as Fig: l: showingt'a rear elevation thereof.

Fig. 3 is' a. top plan View of the freezing unit with the coverplate and insulation removed.

Fig. 4 is' a section taken on the line 4--4* of Fig. 3.

Fig. 5 is -an enlarged sectional viewthroughthe freezing unit, platen, andagittttihg plate;

Fig. dis a central vertical section through a. discharged ice" cube;

Fig; '7 is'a wiringdiagram" of the-electric-comtrol. circuits:

Fig. 8. is a: partial elevation showing the relation' of the platen elevating cam and follower afterinitialiopening movement:

Fig. 9' is" the same as- Fig; 8" afterice freeing of' the platen:

Fig: 10 is the same as: Fig; 8 platen lowered position.

Fig; 11' is'a view from-the-opposite side of the cam from'Fig: 1, showing it in the'same; or platen raised position;

' In the drawings thereis shownanicecube' producing machine havingia supporting'frame structime including a bottom framem'ember H}; uprights ll, top-framemember t2; and cross frame members" l3". and M. In the lower compartment of the frame" structure'and below theframe member l4 there is mounted" a suitable" refrigeratingapparatus ofany wellknownmake; shownherein for' example, ashavinga condenser l 5-and' a motor' driven compressor l 6' arranged to compress-a gaseous refrigerant and' deliver it tothe condenser and from the condenser to-thereceiver ti; all as generally referred to-in the above'menti'oned application. 7

In the upper section of the framestructure there is provided a freezing unit-including a pluralityof individualcubeforming cells open at theirtop-and bottom as shown-in- Figs. 3-, 4 and 5; Said cells-are in-the -form ofisquaresleeves de fined-by the'partiti'on walls- 8 crossed by: transversely extending partition walls l- 9; all of which are surrounded by the outer wall's -z'fl of greaterdepth. The outer'walls 20: are formed with inwardly: extending top flanges: 21- upon the supporting frame 22' is bolted-and spaced by the spacing sleeves 23v. 7

Each of the partitionwalls I 9 of the cells is formed with a top flange 24 extending approximately half way to the next adjacent wall to partially close the top of each cell, but primarily to provide a heat exchange support for the circuitous refrigerant coils 25 as shown in Figs. 3 and 4. Said coils provide the passageway through which the refrigerant is caused to flow in the direction of the arrows. tubes secured in intimate contact and substantially coextensive with the flanges 24 of the cell walls 19 to provide efiicient heat exchange therebetween.

The liquid such as water to be frozen is discharged into the freezing unit through the tube 25 below, but adjacent the liquid level 35. Said tube 28 is connected with a source of supply indicated at 21 which is controlled by the hand valve 28. In the tube 26 there is provided a solenoid actuated shut ofi valve indicated at 29 controlled by a micro switch 30 having a float con-v trolled arm 3l, which is in turn operated by the stem 32 carried by a float within the float chamber 33. Said chamber is connected by the duct 34 with the freezing unit and cells adjacent the lower portion thereof. Thus, the liquid to be frozen is introduced into the freezing unit to a predetermined liquid level in the cells as indicated at 35, whereupon the flow of liquid thereto is automatically shut off by the float controlled valve. The liquid will be distributed to each of the cells within the outer walls 20 to flow below the cell partitions I8 and I9.

Surrounding the freezing unit there is a wall of insulating material 35 covered by a top layer of insulating material 36a. For closing and sealing the unit from the bottom there is provided a platen 31 having a rubber sealing gasket 38 adjacent its edges adapted to engage the outer walls 20. Said platen 31 carries over its lower surface a layer of insulating material 39 and about its sides and rear edges outer insulating strips 40 which are adapted to engage the walls 36 to provide an insulated closure for the freezing unit and platen when the latter is in its closing and sealing position as shown in Fig. 5.

Said platen carries within the sealing gasket 38 an agitating plate 4 l which is coextensive with the cells of the unit. Said plate is provided with a series of apertures 42, each being centrally disposed with respect to said cells. Suiilcient space is provided between the platen '31 and the lower edges of the cell partitions [8,19 to permit a slight reciprocatory movement of the agitating plate toward and away from the cells as indicated by full and dotted lines in Fig. 5. Through this action the liquid to be frozen is gently agitated, while on the downward stroke small streams are projected upwardly and centrally of each cell through the respective apertures 42. Thus, through the reciprocating movement of the agitating plate, there is an agitation of the liquid in each cell with an intermittent pulsating stream directly upwardly and centrally thereof.

Due to agitation of the liquid in each cell and the pulsating stream centrally thereof, ice may gradually form over the surface of the partitions l8, l9 progressively toward the center with a continuous washing away of impurities as the ice is formed. It is well understood to be the tendency of the freezing action to expel entrapped air and impurities provided they are carried away as the ice is being formed, and it is the purpose of the pulsating streams of liquid injected centrally They are in the form of flattened impurities and entrapped air into the center of the cell, so that they will not be entrapped by the ice being formed. Through this medium the formed ice becomes clear, and the usual cloudiness due to entrapped air and impurities is thereby eliminated. However before the center core of each cube is frozen, which would then trap the concentrated impurities, the freezing cycle is terminated and upon discharge of the cubes the remaining liquid and impurities are drained away.

As illustrative of the above there is shown in Fig. 5 a pulsating stream of liquid indicated at 43 within a shell of ice being built up about the partitions I8, [9 as indicated at 44, resulting in the finally formed ice cubes 44a shown sectionally in Fig. 6.

For eifecting the reciprocating action of plate 4|, it is provided with a plurality of downwardly extending rods 45 secured thereto at their upper ends by the screws 66, the upper end of each rod is reduced to receive a flexible sealing gasket 41 secured about its outer periphery within a recess of the platen by an anchor ring 48. Surrounding the upper portion of each rod there is a bearing sleeve 49 through which the rod may reciprocate, the bearing sleeve being surrounded by a block of insulating material 50. Said rods are arranged in opposed pairs, and secured to spring 51 for yieldingly maintaining the rollers 52 in engagement with their respective cams 55. The shaft 54 is driven through a coupling 54a by the motor 55. Through the driving action of the motor cams 55 are rotated to impart the reciprocating action through the platen to the agitating plate 4| for the purposes above described.

The refrigerant coils 25 constituting the evaporator receives the refrigerant from the liquid receiver I! through the refrigerant tube 68, drier 6i, and expansion valve 62. The expansion valve is provided with the usual thermal controlled bulb 62a attached to the outflow portion of said duct 64. From the expansion valve the liquid enters the refrigerant coils 25 through the intake end thereof at 63. The coils of the evaporator at the discharge end wrap around the freezing unit returning the refrigerant through the duct 64 to the suction line 65 (Figs. 2 and 3) and compressor [6. During the freezing cycle the temperature is dropped to a predetermined low after a time interval depending upon the temperature of the liquid delivered to the freezing unit. Upon reaching such predetermined low temperature the thermostatic control bulb 66 (Fig. 2) causes the refrigerant circuit to be reversed for providing a reverse flow of refrigerant such as to direct the hot gases through the refrigerant coils 25 of the evaporator. This is for the purpose of inducing a thawing action for lubrication of the ice formed in the cells to free them and permit them to drop by gravity upon lowering of the platen 31. The thermo bulb 66 is secured adjacent the outer wall 20 of the freezing unit and is connected by the tube 6! to suitable bellows within the temperature controller 68, which controller through bellows iaction controls an adjustable low temperature mercury switch 69 and hightemperaturermercury switch 690. (Fig. 7). SwitchflBS causessthe hot'gas valve 19 .to open whichv permits the hot gas to fiow directly from the compressor to the coils of the evaporator, by-passingthe condenser, through the hot gas connections H However, the operation of the low temperature switch 69 through the temperature controller 68 is momentary or of a short duration only s-ufiicient to energize the cam motor '12, since the hot gases immediately causea suiiicient rise of temperature in bulb (it, to reversely actuate the bellows and cause the low temperature switch 69 to open. Upon the cam motor #2 being energized and cam [5 partially rotated the hold switch l3 (Figs. '7 and 11) is closed which maintains a closed circuit through thehot gas valve Ill and cam motor it. after the low temperature switch 59 opens. Hold switch i3 is closed by cam 88 riding on the end of its. switch leverlSc upon the initial movement of cam 15. The hold switch 13 remains closedduring one complete revolution of the cam shaft i l driven by motor I2 after which it opens the circuit through the hot gas valve 16 and, closes the circuit through the float switch to open the liquid shut off valve 29 for recharging the freezing unit. This occurs when cam 88 again engages the switch lever 13a.

Upon the cam motor 12 being energized, the shaft 14 rotates the cam 15 (Fig. 1) in the direction of the arrow (Figs. 8 to 11). Cam 15 has a cam follower [6 in the. form of a roller carried on a lever ll. One end of lever H is pivoted at Ha to a bracket [8 carried by the frame. At the other end of lever 11 there is pivotally mounted an adjustable link 19 having its opposite end pivoted at 19a between the brackets 53 secured to the platen 3i. ihe platen 3? is supported at its rear end upon the rear uprights ll of the frame by a pair of links 80 whichare restricted in their downward drop by adjustable stop screws 8| carried by the brackets 82.

When the cam 15 is in the position shown in Fig. 1 with the follower l6 engaging its extending face, it holds the platen in its closed sealing engagement with the freezing unit as shown in Fig. 5. Upon rotation in the direction of the arrow the follower rides. over the reduced portion of the cam permitting the platen to. be lowered to its ice discharge position shown. by dotted lines in Fig. l. Said platen is lowered to an inclined position for discharging the ice cubes that are released from the cells upon the thawing action of the reverse flow hot refrigerant. However upon initial release both by the action of said cam and the thawing of the ice, it. is slightly tilted by a spring 83. Said spring has one end connected to an arm 84 secured to one of the brackets 53 and the other end securedto a pivot connection between lever 11 and link '19. As the spring is off center toward the forward end of the platen, it will cause the platen (to first tilt downwardly to discharge excess liquid before the full lowering thereof. Further movement of the cam 15 with further lowering of the platen causes its rear end to move downwardly to, the limit of movement of the links 80 at which position the platen will be arrested in its downward movement through the medium or the micro switch 85 in substantially parallel relation to the freezing unit.

The switch .85 is mounted on the lever Ti.

dotted lines in Fig. 1.

1' be no discharge of ice cubes at such time.

Its purpose is to break the circuit to .the cam motor 12 after a short initial movement of the cam 15 until the platen is free to tilt down upon the release from the ice. Said switch is normally closed until the cam follower 16 drops relative to the lever T1 in its elongated bearing slot .Hia'through the initial movement of the cam 15,.the lever being momentarily held in its upper position by the adhesion of the platen to the ice (Fig. 8). However, as soon as the platen is releasedso that the lever may drop (Fig. 9), raising the cam. follower relative thereto, switch arm-86 is thereby actuated to again close the switch whereupon the motor drives .the cam .through a half cycle until the micro-switch is again'opened (Fig. 10). Such rotation of .the cam permits theplaten to tilt downwardly to its full inclined discharging position as shownby It is arrested in this position by a suitable stop indicated at 31a opening switch 85. After discharging the ice, it will be returned to its closing and sealingposition (Fig. 11) upon the high temperature switch 69a in the controller 58 being closed.

The motor (2 drives cam shaft "Hi through suitable reduction gearing mounted within the gear housing 31. The hold switch 13 is mounted upon the cross frame l4 immediately below the cam shaft '54 which carries the switch actuating cam 88 adapted to engage the switch lever 13a to open the circuit through the cam motor upon completion of the.cycle and close the circuit through the float switch 30 to open the liquid valve and permit a fresh charge of liquid to enter the freezing unit.

On the forward uprights H there is mounted an ice receptacle Bil removably seated in a fixed supporting tray 98a having a drain pipe 9! leading to the drain outlet S2 for receiving charges of ice cubes from the platen 3'! when in its inclined discharging position. Said receptacle is closed by a cover lid 93 hinged at 93a to the uprights ll. Intermediate the end of the platen and the receptacle there is a sloping drain chute 9 which may be in the form of a screen over which the ice cubes slide, but which permits the freed and-unfrozen liquid to pass therethrough into a drain receptacle 95 from which the liquid passes through the discharge pipe 96 to the outlet 92.

When the receptacle 9c is in place on its supporting tray it closes the switch 91 in the circuit shown in Fig. 7, said switch being opened when the receptacle Bil is removed so that there will Adjacent the upper portion of the ice receptacle there is a thermo bulb 98 which leads through the tube 99 to a thermal switch i061 which operates. to break the circuit and stop the machine when the receptacle 9B is suiiiciently full of ice cubes to reduce the temperature of the bulb 9%. By means of this control the machine will automatically discontinue its operations when the receptacle is filled with cubes so that there will be no overflow, the switch I I30 being normally closed.

As shown herein the freezing unit contains 156 as shown in Figs. 1 and 5. The float controlled switch 30 being closed and the cam actuated hold switch 13 closing the circuit therethrough (Fig. 11), liquid to be frozen is permitted to pass through line 26 and valve 29 into the cells until the liquid level 35 is reached. The float in chamber 33 will then open the switch 38 to break the circuit through valve 29, closing said valve and shutting off further inflow of liquid.

Refrigerant gases will circulate in the direction of the arrows through the refrigerating coils 25, the reverse flow or by-pass valve 18 being closed. With the low temperature thus produced in the freezing unit, ice will begin to form at 44 on the partitions l8, IQ of the cells as shown in Fig. 5. The motor 56 will operate during the introduction of the liquid into the cells and the freezing thereof, causing reciprocating action of the agitating plate 4| so that there will be a pulsation of the liquid in each cell accentuated by the central stream 43 forced through apertures 42 in the plate (Fig. 5).

Due to the position of the inlet pipe 26 adjacent but below the liquid level, ice will first freeze over the inlet and prevent additional liquid from entering the unit should contraction or agitation thereafter cause the float to drop and close the circuit through valve 29 to momentarily open it.

Upon the temperature in the freezing unit, due to the building up of ice, reaching a predetermined low temperature the thermo bulb 66 leading to the temperature controller 68 will cause the low temperature mercury switch 69 to momentarily close a circuit to the hot gas valve to open it and thereby cause a reverse flow or bypass of hot refrigerant. The reverse fiow of the refrigerant through the tubes 7|, by-passing the condenser i5, will pass hot gases through the refrigerant coils 25 such as to cause sufficient melting of the ice adjacent the partitions I8, H! to free the cubes from their respective cells, and through the normally closed micro switch 85, cam motor 12 will be energized to rotate cam sufiiciently far to permit the cam follower 16 to drop down (Fig. 8) in position to open said switch and arrest the cam motor and further movement of the cam. This initial movement of the cam 15 will cause the actuating cam 88 to ride off the end of switch lever 13a to reverse hold switch 13 (Fig. 11) for holding valve 10 open. At this point, the platen will be free to move downwardly away from the freezing unit by gravity only a slight distance. However, it may be held in its closed position by the ice frozen to its gasket, but as the defrosting takes place, the platen soon breaks away freeing itself and tilting slightly about its pivotal connection with the links 80 through action of the spring 83. Thereupon the excess liquid in the unit will be freed to flow into the drain receptable 95.

Upon ice release of the platen, its weight will be carried by the cam follower 15, the lever 11 moving downwardly relative thereto suificiently to cause the cam follower to close switch 85 (Fig. 9) and again operate the cam motor 12. The cam 15 will then permit the platen to lower to its extreme inclined position shown in dotted lines in Fig. 1 and the ice cubes will drop from their respective cells on to the inclined platen as they are released by the reverse flow of the refrigerant, whereupon they slide downwardly over the drain 94 into the reecptacle 90. At this point, with cam 15 in its lowermost position (Fig. 10)

8 below follower 18, switch 85 will again be opened to arrest cam 15 with the platen lowered.

After complete discharge of the ice, the temperature in the freezing unit will have risen sufficiently to cause the thermo bulb 66 to move the bellows in the temperature controller 68 to a predetermined high temperature position whereupon the high temperature mercury switch 69a will close. This switch again closes the circuit through the cam motor 12 causing the cam 15 to elevate the platen to its closing and sealing position. The cam 15 will thereupon have made one complete revolution which will bring the switch actuating cam 88 into engagement with the switch lever 13a of switch 13 to finally break the circuit through the cam motor 12 (Fig. 11) and the hot valve i0 which will thereupon be permitted to close so that the refrigerant will flow from the condenser through the refrigerant coils 25 to again reduce the temperature of the freezing unit. At the same time, switch 73 will close the circuit through the closed float switch 30 to energize liquid valve 29 and permit a fresh charge of liquid to enter the cells.

The invention claimed is:

1. In an ice cube making machine, the combination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle, means for introducing into said cells a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein, an agitating member interposed between the bottom of said cells and said plate, and means operably connected'with said member for imparting movement thereto to effect an agitation of the liquid during the freezing cycle.

2. In an ice cube making machine, the combination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle, means for introducing into said cells a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein, a movable member submerged in the liquid at the bottom thereof, and means for continuously moving said member to effect an agitation of the liquid during the freezing cycle.

3; In an ice cube making machine, the combination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle, means for introducing into said cells a liquid to be frozen into ice cubes, means for refrigerating said imit to freeze the liquid therein, a pulsating member interposed between said cells and. plate provided with a liquid emitting orifice substantially centrally of each cell, and means connected with said member for effecting pulsations of the liquid through said orifices into each of said cells for agitating the liquid confined therein during the freezing cycle.

4. In an ice cube making machine, the combination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle, means for introducing into said cells a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein. an apertured plate extending between the bottom of said cells and closure plate to provide a pulsating orifice for 9 each cell, and means for reciprocating said agitating plate toward and away from said cells for withdrawing liquid therefrom and discharging it upwardly through said "orifice for maintaining the liquid in each cell in 'an agitated condition during the freezing cycle.

5."In an ice cube making machine, the com.- bination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle, means for introducing into said cells a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein, a pulsating member interposed between said cells and closure plate submerged at the bottom of the liquid and provided with an aperture below each cell, and driving mechanism connected to said member through said closure plate operable to impart an up'and down stroke thereto for ejecting a pulsating stream of liquid upwardly throughout the depth thereof on each down stroke to effect liquid agitation during the freezin cycle,

6. In an ice cube making machine, "the combination of a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit adapted to engage and seal. said unit during the freezing cycle and in spaced relation to the lower edges of the cells, means for introducing into said cells. and the space between said cells and closure plate a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein, an apertured agitating plate carried by said closure plate coextensive with said cells, the apertures therein arranged substantially centrally thereof, and means on said closure plate extending therethrough .in operative engagement with said aperture agitating plate for imparting a reciprocating movement thereto toward and away from said cellssubmerged within the liquid between said cells and closure plate for ejecting a stream of liquid through each aperture upwardly into the respective cells on each downward movement of said apertured plate during the freezing cycle.

7. In an ice cube making machine, the combination of :a freezing unit comprising a plurality of cells normally open at the bottom, a closure plate for said unit adapted to engage and seal said unit during the freezing cycle and in spaced relation to the lower edges of the cells, means for introducin into said cells and the space between said cells and closure plate a liquid to be frozen into ice cubes, means for refrigerating said unit to freeze the liquid therein, and a pulsating platecoextensive with said cells mounted for reciprocating movement in the space between said cells and closure plate in a direction toward and from said cells, andmeans for reciprocating said plate to produce a turbulence of the liquid within the cells and throughout the depth there of during the freezing cycle.

8. In an ice making machine, the combination with a freezing unit having a plurality of open bottom cells for receiving a liquid to be frozen and a removable closure therefor, of a pulsating member submerged within the liquid adjacent said closure, and means connected with said member operable to impart a pulsating action thereto for agitating the liquid in said cells during the freezing operation.

9. In an ice making machine, the combination and aremovable closure therefor, of an agitating member movably mounted between said closure and the bottom of said cells, and means connected with said member for imparting movement thereto while submerged in the liquid between said cells for agitating the liquid therein during the'freezing cycle. I

10. The combination with a freezing cell for receiving liquid to'be frozen to a solid state, of an agitating pla'te submerged in the liquid below the cell movable toward and away therefrom, said plate having a single aperture centrally located relative to said cell and means for moving said plate vertically relative tosaid cell for forcing a stream of liquid through the aperture, therein to effect agitation of the liquid in the cell during the freezing cycle.

ll. A freezing unit for an ice cube making machine adapted to receive the liquid to be frozen therein comprising a plurality of cells defined by one parallel seriesof spaced vertical walls extending transversely to a second parallel series of spaced vertical walls, said walls being of heat conductive material, one series of said walls be ng formed with an inwardly turned flange along its upper edge. a refrigerant evaporator comprising a sinuous tube secured to said flanges in heat convection engagement and means for passing a refrigerant through said tube to freeze the liquid in said cells. j

12. A freezing unit for an ice cube making ma.- chine adapted to receive the liouid to be frozen therein comprising a plurality of cells defined by one parallel series of spaced vert cal walls extending transversely to a second parallel series of spaced vertical walls, an eva orator in the form of a sinuous refrigerant conducting tube extending over said cells, laterally extendin flanges formed on one series of said walls for supporting and securing said tube thereon in heat conductive relation and means for passing a refrigerant through said tube to freeze the liquid in said cells.

13. A freezing unit for an ice cube makin mac'hineadapted to rece ve the li uid to be frozen therein com rising a plurality of cells defi ed by one parallel series of spaced vertical walls extending transverselv to a secon para lel series of spaced vertical walls, said walls being of heat conductive material, one series of sa d walls being formed with an inwardly turned f anged along its upper ed e, a sinuous tube flattened to form an under-surface of substantial width secured to said flanges in heat con uctive relation therewith whereby a substantial heat transfer surface will be provided therebetween and means for passing a refrigerant through said tube to freeze the liquid in the cells.

14. In 2. ice cube making machine, the combination of a freezing unit normally open at the bottom, a closure plate for said unit movable to close and seal the bottom of said unit during the freezing cycle and means for refri erating a liquid in said unit, of a pivotally mounted lever having a link connection with said plate, a cam movable to raise said plate into sealing en agement with said unit and permit it to drop therefrom to discharge position, an electric motor for driving said cam, and switch control mechanism for the circuit to said motor operable to arrest the movement of said cam after releasing said plate from sealing engagement with said unit until said plate is freed from the frozen liquid to drop a predetermined distance, and thereuponcontinue the movement of said cam to permit the dropping of said plate to its lowermost discharge position.

15. In an ice cube making machine, the combination of a freezing unit normally open at the bottom adapted to receive liquid to be frozen therein, means for refrigerating said unit to freeze said liquid and a closure plate for said unit movable to close and seal the bottom thereof during a freezing cycle, of a pivotally mounted lever having a link connection with said plate, a cam movable to raise said plate to sealing engagement and permit the lowering thereof from said unit to discharge position, a cam follower carried by said lever movable relative thereto to one position under pressure of said camand to another position when freed therefrom, an electric motor for driving said cam, and a switch for controlling the circuit of said motor operable by said follower to break the circuit to the motor upon said cam being moved free of said follower for limiting the dropping of the plate after it is freed from the frozen liquid, and closesaid circuit upon follower pressure by said cam to continue the movement of the cam to permit lowering of said plate to its full discharge anism operable at the conclusion of the freezing cycle to remove said closure plate and permit discharge of the unfrozen'liquid and frozen ice cubes from the freezing unit, and a drainage member below and spaced from said closure plate for receiving the unfrozen liquid and ice cubes therefrom and separating them to direct said ice cubes into one receptacle and permit the unfrozen liquid to pass into another receptacle.

17. In an ice cube making machine, the combination of a freezing unit normallyopen at the bottom, a closure plate for said unit movable to close and seal said unit during a freezing cycle and open said unit following the freezing cycle, means for introducingta liquid to be frozen into said unit, means for refrigerating said unit to freeze a portion of the liquid therein, means for discontinuing the refrigeration of said unit following the freezing of a portion of the liquid and releasing said closure plate to'permit the frozen and unfrozen liquid to drop from said unit, and a sloping drainage screen positioned below said freezing unit for receiving the frozen and unfrozen liquid therefrom upon said closure passing a refrigerant therethrough to reduce the I temperature of the walls progressively from the top downwardly, of a liquid conduit connected with the wall of said cell adjacent and below a predetermined liquid level therein, a valve in said conduit operative to shut off the supply of liquid to said cell upon the liquid therein reaching a predetermined level, and means for effect ing removal of frozen liquid from said cell upon completion of the freezing cycle and permit a new charge of liquid thereto, the connection of said liquid conduit with the wall of the cell becoming closed through ice formation thereover by reason of its submerged proximity to the refrigerating element for preventing additional liquid from entering said cell through opening of said valve upon momentary lowering of the liquid level.

19. In an ice making machine, a freezing cell for receiving a liquid to be frozen, a source of liquid supply having an inlet conduit connected with one wall of said cell below a predetermined liquid level therein but within close proximity of a refrigerating element associated therewith for forming an ice cap over said inlet during the initial freezing action, and a valve operative to close said conduit upon the liquid reaching a predetermined level in said cell, whereby liquid will be prevented from entering said cell after the initial closing of said valve in event of momentary drop of the liquid level during the freezing cycle.

GUSTAV F. ERICKSON. DORMON B. McSHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 163,142 Boyle May 11, 1875 666,269 Hamilton Jan. 22, 1901 1,449,225 Griesser Mar. 20, 1923 1,757,033 Wolcott May 6, 1930 2,023,923 Harbordt Dec. 10, 1935 2,069,195 Chilton Feb. 2, 1937 2,432,597 Toulmin Dec. 16, 1947 2,449,132 Lucia Sept. 14, 1948 

